Requires Mg2+. The enzyme, isolated from the bacterium Streptomyces fradiae, is involved in the biosynthesis of the macrolide antibiotic tylosin. The 2-hydroxy group of a 6-deoxy-D-allose moiety in demethylmacrocin acts as the methyl acceptor. Also acts on demethyllactenocin, giving lactenocin. Not identical with EC 2.1.1.101 macrocin O-methyltransferase.